A work machine like an excavator includes a working unit having a bucket, an arm, and a boom. A plurality of hydraulic pumps is mounted on the work machine as a drive source of a hydraulic cylinder that drives the working unit.
Patent Literature 1 discloses a hydraulic circuit including a merging and splitting valve that switches between a merging state in which operating oil discharged from a first hydraulic pump and operating oil discharged from a second hydraulic pump merge together and a splitting state in which the operating oil from the two hydraulic pumps is split. When the first hydraulic pump and the second hydraulic pump are in the merging state, the operating oil discharged from the first hydraulic pump and the operating oil discharged from the second hydraulic pump are merged by the merging and splitting valve and are distributed to a plurality of hydraulic cylinders. When the first hydraulic pump and the second hydraulic pump are in the splitting state, a boom cylinder operates with the operating oil discharged from the first hydraulic pump and a bucket cylinder and an arm cylinder operate with the operating oil discharged from the second hydraulic pump.
Patent Literature 2 discloses a technique of providing a pressure compensation valve between a main operating valve and a hydraulic actuator to equalize a front-rear pressure difference of a main operating valve connected to each of the plurality of hydraulic cylinders when a first hydraulic pump and a second hydraulic pump are in a merging state. When the front-rear pressure difference of the plurality of main operating valves is equalized, since operating oil is supplied to the hydraulic cylinder with a flow rate corresponding to an operation amount of an operating device, a decrease in the operability of the operating device is suppressed.